(1) Field of the Invention
The present invention pertains to a mechanical locking apparatus that is assembled to an existing cooling tower fan assembly and is operable to brake the drive shaft of the fan assembly, keeping the fan from rotating in high winds.
(2) Description of the Related Art
A cooling tower is a structure that is used to cool a liquid, typically water, that is heated by the operation of an air conditioning system of a large building, a refinery, a petrochemical facility, a manufacturing facility, an electric power generation facility, or other similar facility. The cooling tower is typically constructed on the top of a building or other similar structure, or in an open area of a refinery, petrochemical facility, power generation facility, etc. where it is directly exposed to the atmosphere. The heated water is directed into the interior of the cooling tower and falls by gravitation over surfaces in the tower interior. The surfaces spread the heated water, exposing the water to the atmosphere which results in cooling of the water. To assist in cooling the water, large fan assemblies are typically employed to produce an induced draft through the cooling tower. In each fan assembly, a fan is mounted on a reduction gearing system that is rotated by a drive shaft connected to a motor. Rotation of the fan produces a counter flow or cross flow of cooling air upwardly or crosswise through the tower, opposite or perpendicular to the downward flow of the water to be cooled.
The construction of the typical cooling tower is open to the atmosphere to assist in the cooling of the heated water passed through the tower. This open construction exposes the fan in the tower to high winds. In very high wind situations produced by storms, in particular by hurricanes, the high winds can cause the fan to rotate at a high rate of speed. As wind speeds increase, the fan will rotate faster and faster. When the high winds reach a point that the wind load on the cooling tower fan stack surrounding the fan causes the fan stack to flex toward the rotating fan blades, the rotating fan blades can impact with the flexing cooling tower fan stack. Due to the rotating speed of the fan, the impact can shatter the fan, damage the reduction gearing and the drive shaft of the fan, and damage the cooling tower fan stack surrounding the fan, making the fan stack more susceptible to being torn from the cooling tower on the roof top of a building or in the open area of a refinery, petrochemical facility, power plant, etc., by the high force winds.